Economic consequences of low fertility in Europe

This paper focuses on possible economic consequences of low fertility in Europe. It summarizes a selection of papers that were presented at a conference at the University of St. Gallen in April 2008. This introduction also reviews the history of falling fertility in Europe and the literature that explores its causes, its potential implications, and possible policy responses. It summarizes the evolution of thinking about the relationship between population growth and economic development, with attention to recent work on the mechanisms through which fertility decline can spur economic growth if the necessary supporting conditions are met. The paper also identifies some of the challenges of population aging that are associated with low fertility and suggests that there may be less reason for alarm than has been suggested by some observers. --

Economic Consequences of Low Fertility in Europe

This special issue of the European Journal of Population focuses on possible economic consequences of low fertility in Europe. This introduction reviews the history of falling fertility in Europe and the literature that explores its causes, its potential implications, and possible policy responses. It also summarizes the evolution of thinking about the relationship between population growth and economic development, with attention to recent work on the mechanisms through which fertility decline can spur economic growth if the necessary supporting conditions are met. The introduction also identifies some of the challenges of population aging that are associated with low fertility and suggests that there may be less reason for alarm than has been suggested by some observers. The papers that appear in this special issue are also summarized.Economic consequences, low fertility, Europe

Keratinocytes from human skin respond as typical immune cells after the stimulation with _Trichophyton rubrum_

_Trichophyton rubrum_ is the main agent causing dermatophytosis (1). Keratinocytes are
considered to be the first physical barrier of defense against pathogens (2). But not
only a physical barrier. They recognize antigens through Toll like receptors (TLR) (3).
The activation of this TLR, present on the surface of the keratinocytes, induce the
expression of different pro-inflammatory cytokines, co-stimulatory molecules and
antimicrobial peptides such as [beta]-defensins (4).
The main objective of this work is to determine if lipopolysaccharides of G – bacteria
(LPS), lipotheichoic acid from G+ bacteria (LTA), and conidias, isolated from _T. rubrum_
were able to activate the expression of TLR2 and TLR6 on the cell surface of a primary
culture of human keratinocytes through Flow cytometry. Furthermore we are looking for
the presence of [beta]-defensins 1 and 2, IL-1b and IL-8 in the supernatant, of the above
mentioned culture of cells, by Western blot.
From the flow cytometry data, the preliminary results showed an important dispersion
in terms of proliferation, increase in size and granularity of keratinocytes, from primary
cultures of skin from healthy donors, stimulated 6 hours with conidias of _T. rubrum_, and
LTA, but not when non stimulated, or stimulated with LPS (Fig 1).
When keratinocytes from primary cultures of skin from healthy donors were cultivated
48 hours, it was found dispersion in terms of proliferation, increase in size and
granularity when stimulated with conidias of _T. rubrum_, and LPS but not when non
stimulated, or stimulated with LTA (Fig 2).
The keratinocytes expressed increased levels of TLR2 and TLR6 when were
stimulated with LTA and less to _T. rubrum_, in the 6 hours cultures, but this last cells still
showed increased size (Fig 3).
The Keratinocytes expressed increased levels of TLR2 in the 48 hours cultures when
were stimulated with LPS and _T. rubrum_.(Fig 4)
Besides, [beta]-defensin-2 was detected in the supernatant of cultures of keratinocytes
stimulated with LPS (Fig 5).
It can preliminary be concluded that keratinocytes from primary cultures of human skin from healthy donors, are cells that respond as typical immune cells, after stimulation
with _T. rubrum_, LTA and LPS in different conditions, and that this mechanism may be
very important, for the protection of local environment. 

References
1.- Arenas R., Dermatofitosis en México. Rev Iberoam Micol 2002; 19: 63-67.
2.- Kupper T. and Fuhlbrigge R. Immune surveillance in the skin: mechanims and clinical consecuences.
Nat Rev Immunol 2004; 4: 211-222
3.- Kôllish G., Naderi B., Voelcker V., Wallich R., Behrendt H., Ring J., Bauer S., Jacob T., Mempel M. and
Olelrt M. Various members of the Toll-Like receptor family contribute to the innate immune response of
human epidermal keratinocytes. Immunology 2005; 114: 531-541.
4.- Akira, S. and Takeda K. 2004. Toll-like Receptor Signalling. Nature Reviews Immunology 4:499-511

Inflowing gas onto a compact obscured nucleus in Arp 299A: Herschel spectroscopic studies of H2O and OH

Aims. We probe the physical conditions in the core of Arp 299A and try to put constraints to the nature of its nuclear power source. Methods. We used Herschel Space Observatory far-infrared and submillimeter observations of H2O and OH rotational lines in Arp 299A to create a multi-component model of the galaxy. In doing this, we employed a spherically symmetric radiative transfer code. Results. Nine H2O lines in absorption and eight in emission as well as four OH doublets in absorption and one in emission, are detected in Arp 299A. No lines of the 18O isotopologues, which have been seen in compact obscured nuclei of other galaxies, are detected. The absorption in the ground state OH doublet at 119 {\mu}m is found redshifted by ~175 km/s compared to other OH and H2O lines, suggesting a low excitation inflow. We find that at least two components are required in order to account for the excited molecular line spectrum. The inner component has a radius of 20-25 pc, a very high infrared surface brightness (> 3e13 Lsun/kpc^2), warm dust (Td > 90 K), and a large H2 column density (NH2 > 1e24 cm^-2). The outer component is larger (50-100 pc) with slightly cooler dust (70-90 K). In addition, a much more extended inflowing component is required to also account for the OH doublet at 119 {\mu}m. Conclusions. The Compton-thick nature of the core makes it difficult to determine the nature of the buried power source, but the high surface brightness indicates that it is either an active galactic nucleus and/or a dense nuclear starburst. The high OH/H2O ratio in the nucleus indicates that ion-neutral chemistry induced by X-rays or cosmic-rays is important. Finally we find a lower limit to the 16O/18O ratio of 400 in the nuclear region, possibly indicating that the nuclear starburst is in an early evolutionary stage, or that it is fed through a molecular inflow of, at most, solar metallicity.Comment: 14 pages, 13 figures, Accepted for publication in Astronomy and Astrophysic

Practice-oriented controversies and borrowed epistemic credibility in current evolutionary biology: phylogeography as a case study

Although there is increasing recognition that theory and practice in science are intimately intertwined, philosophy of science perspectives on scientific controversies have been historically focused on theory rather than practice. As a step in the construction of frameworks for understanding controversies linked to scientific practices, here we introduce the notion of borrowed epistemic credibility (BEC), to describe the situation in which scientists, in order to garner support for their own stances, exploit similarities between tenets in their own field and accepted statements or positions properly developed within other areas of expertise. We illustrate the scope of application of our proposal with the analysis of a heavily methods-grounded, recent controversy in phylogeography, a biological subdiscipline concerned with the study of the historical causes of biogeographical variation through population genetics- and phylogenetics-based computer analyses of diversity in DNA sequences, both within species and between closely related taxa. Toward this end, we briefly summarize the arguments proposed by selected authors representing each side of the controversy: the ‘nested clade analysis’ school versus the ‘statistical phylogeography’ orientation. We claim that whereas both phylogeographic ‘research styles’ borrow epistemic credibility from sources such as formal logic, the familiarity of results from other scientific areas, the authority of prominent scientists, or the presumed superiority of quantitative vs. verbal reasoning, ‘theory’ plays essentially no role as a foundation of the controversy. Besides underscoring the importance of strictly methodological and other non-theoretical aspects of controversies in current evolutionary biology, our analysis suggests a perspective with potential usefulness for the re-examination of more general philosophy of biology issues, such as the nature of historical inference, rationality, justification, and objectivity

Sound focusing by gradient index sonic lenses

Gradient index sonic lenses based on two-dimensional sonic crystals are here designed, fabricated and characterized. The index-gradient is achieved in these type of flat lenses by a gradual modification of the sonic crystal filling fraction along the direction perpendicular to the lens axis. The focusing performance is well described by an analytical model based on ray theory as well as by numerical simulations based on the multiple-scattering theory.Comment: 4 pages, 4 figure

Modeling the H2O submillimeter emission in extragalactic sources

Recent observational studies have shown that H2O emission at (rest) submillimeter wavelengths is ubiquitous in infrared galaxies, both in the local and in the early Universe, suggestive of far-infrared pumping of H2O by dust in warm regions. In this work, models are presented that show that (i) the highest-lying H2O lines (E_{upper}>400 K) are formed in very warm (T_{dust}>~90 K) regions and require high H2O columns (N_{H2O}>~3x10^{17} cm^{-2}), while lower lying lines can be efficiently excited with T_{dust}~45-75 K and N_{H2O}~(0.5-2)x10^{17} cm^{-2}; (ii) significant collisional excitation of the lowest lying (E_{upper}<200 K) levels, which enhances the overall L_{H2O}-L_{IR} ratios, is identified in sources where the ground-state para-H2O 1_{11}-0_{00} line is detected in emission; (iii) the H2O-to-infrared (8-1000 um) luminosity ratio is expected to decrease with increasing T_{dust} for all lines with E_{upper}<~300 K, as has recently been reported in a sample of LIRGs, but increases with T_{dust} for the highest lying H2O lines (E_{upper}>400 K); (iv) we find theoretical upper limits for L_{H2O}/L_{IR} in warm environments, owing to H2O line saturation; (v) individual models are presented for two very different prototypical galaxies, the Seyfert 2 galaxy NGC 1068 and the nearest ultraluminous infrared galaxy Arp 220, showing that the excited submillimeter H2O emission is dominated by far-infrared pumping in both cases; (vi) the L_{H2O}-L_{IR} correlation previously reported in observational studies indicates depletion or exhaustion time scales, t_{dep}=Sigma_{gas}/Sigma_{SFR}, of <~12 Myr for star-forming sources where lines up to E_{upper}=300 K are detected, in agreement with the values previously found for (U)LIRGs from HCN millimeter emission...Comment: 13 pages, 13 figure